A South Yorkshire Police spokesman said it would be adopting the same stance as the Met.

In a response to the FOI request, submitted on website whatdotheyknow.com , the force said: “We would classify ‘victims’ of Hillsborough as being those who died, anyone injured, people who were present suffering trauma and stress and the family members of those involved.

“The law of statistics for such a large group means that it is possible that some of them may, at some time, or even currently, be linked to some sort of surveillance, but not because of their links to Hillsborough.

“The police’s use of surveillance is strictly monitored and regulated and is not an activity taken lightly.

“The reasons for doing so are always linked to an investigation and the type of crimes involved can range from theft to more serious matters such as organised crime or even terrorism.”

It said there were public interest factors in favour of confirming or denying the information but revealing it could “impair the prevention or detection of crime and harm national security by rendering security measures less effective”.

The force said it agreed with a statement released by the Met on the matter.

The Met Police statement said: “We have been asked in recent days whether undercover officers were deployed into the Hillsborough campaign.

“We replied that we will neither confirm nor deny details of the deployment of undercover officers.

“This is a long-established practice to avoid criminals targeted for undercover operations drawing conclusions if we were to give negative answers in some cases but not comment in others.

“Once we start denying false or incorrect allegations, our silence in other cases could be taken as a confirmation, and that could be very damaging and dangerous for those who risk their lives to combat organised and serious criminality.”

Similar FOI requests have been submitted to Merseyside Police , West Midlands Police and West Yorkshire Police but responses have not yet been received.